Fuel feeder for furnaces



OCL`3, 1944. P B. GREGER FUEL FEEDER FOR FURNACES 3 Sheets-Shea?l 1 Filed May 9, 1940 vQHcrrneH.

oct. 3, 1944. 'R B. GREGER 2,359,638

FUEL FEEDER FOR FURNACES Filed May 9, l1340 3 sheets-sheet 2 j PAUL 'Get-GER.

' FUEL FEEDER FOR EURNACES t Filed May 9. 1940 3 ySheets-Sheet 5 00000 o Sha-f@ 9%/ m o oooooo o ooooo 0% 6009000 o ooooo 4 o o o O'OO o znvenwr PAUL 5 GEGEE'a Patented Oct. 3, 1944 UNITED STATES PATENT GFFICE FUEL FEEDER FOR FURNACES Paul B. Gregor, Glenside, Pa.

Application May 9, 1940, Serial No. 334,122

6 Claims.

My invention is an improved apparatus for utilizing small size coal, such as rice or barley, and for feeding and distributing such fuel and air in correct proportions for efficient combustion in any suitable type of furnace, but particularly in furnaces of the domestic heating type.

My improvements are preferably embodied in a unit comprising a pneumatic conveyor system having one end sealed by fuel drawn or fed positively into the system,at a measured rate, from a storage bin, and the otherend sealed by fuel being positively ejected from the system, at a measured rate, to a grate having zones of combustion to which the blast which has conveyed the fuel is distributed proportionately to the depth of the fuel bed and the volatility of the fuel in the respective combustion zones.

The introduction and ejection of the fuel into and from the system is preferably effected by worms rotatable in tubes by a suitable motor, which also operates a blower creating a blast, of fue1-carrying intensity, through a conduit oonnected at one end with the blower casing and at the other end with a drum beneath the grate and containing pressure-differentiating chambers in which green fuel, from the conveyor, and partly consumed or coked fuel, from the grate, may be mixed by agitators and overfed to the lower portion of an inclined grate, over which the fuel is distributed by a rotary spreader. The drum chambers are separated by a perforated partition depending into a fuel pool in the drum to a level below the inlet to the vertical tube leading to the grate.` Agitators are rotated in both such chambers oppositely to the direction of rotation of the Worm carrying fuel upwardly from the pool through the vertical tube to the grate and of the spreader which distributes the fuel over the grate.

The characteristic features and advantages of my improvements will further appear from the following description and the accompanying drawings in illustration thereof.

In the drawings, Fig. 1 is a top plan View of a fuel feeding mechanism embodying my invention, with parts broken away for clearer illustration; Fig. 2 is an irregular vertical sectional View of the mechanism taken substantially on the line 2 2 of Fig. 1; Fig. 3 is a front end View of the mechanism shown in Figs. 1 and 2, with part of the casing broken away; Fig. 4 is a fragmentary side view of the blower casing; Fig. 5 is an enlarged broken top plan View of the combustion unit of the mechanism; and Fig. 6 is a transverse sectional View along Een Ilh'e` 6`-6 of the end of a tube 5 containing a lateral; port S.

through which it discharges to-an. axiarll extension I of a blower casing 8. ALshaftj 9 is jours nalled in a packed or substanti,,allgA air-tight bearing I!) in the outer end of tube 5 and has fixed thereon a worm II. edges of a. number of blades of the worm make a, loose slip t with the inner periphery of the tube 5. The free end of the shaft `9 and worm I project from the tube 5 across the trough 3 and agitate granular or powdered fuel therein to facilitate suction thereof through the tube 5` The rate of feed of the ,fuel through the tube 5 is measured by the rate o f rotation of the worm II. The rotation of the Worm may be eected at a pre-determined rate by securing a sprocket I2 to the outer end thereof and connecting such sprocket through a sprocket Chain I3 with a sprocket I4 on the shaft of a speed change gear Il within the housing I. An electric motor I5 is connected through a flexible coupling I6 with the speed change gear I'I and has a shaft I8 journalled in the extension 'I' and casing 8. The shaft I8 has fixed thereto the hub I9 of a blower rotor having vanes 2|)v rotatable in the casing 8 to effect the evacuation of the latter, and the parts communicating; therewith, through the secantial discharge duct;

The duct 2I is connected through a duct 22;, of any desired length, with a duct section 23,= which passes through and is supported by theouter inverted conoidal shell 24 mounted on the; hollow base 26. The duct section 23 discharges; Within an inner inverted conoidal shell 25 de pending from a perforated top 2l, forming a combustion grate; such top being supported by the shell 24.

The surface of the perforated top 2l inclines conoidally downward from its perimeter to the annular edge of the top of an axial tube 28 depending from the grate 21 (Fig. 6). The parts 24, 25, 26 and 28 form a hollow chambered structure herein sometimes referred to as a drum. The number and area of the apertures in the grate zone lying between the shells 24 and 25 and the number and area of apertures in the grate Zone-lying between the shell 25 and tube 28 are proportioned to the amount of primaryare requisite for the proper combustion of a relatively thick bed of raw coal to be burned in the inner zone and of a relatively thin bed of partially de-volatilized coal to be burned in the outer zone. Ths supply of air to the respective zones, to an amount requisite for effecting combustion without clinkering, is further controlled by the size and number of the apertures a in the shell 25 through which alone primary air of combustion is supplied to the fuel in the outer zone of the grate inf/the operation of the apparatus. f

The bottom edge of the cylindrical shell or tube -28 lies in a plane slightly above the level of the bottom edge ofthe shell 25 and the bottom edges of the tube 28 and shell 25 are positioned above ythe bottom level of the shell 24 which rests f on and makes an air-tight joint with the top of the hollow base 26. Y

'Ihe fuel which settles in the bottom of thereceiver from the conveyor and grate'forms a seal between the lower ends of the chambers'29 and 30 formed by the shells 24", 25'and Z'Bfand prevents escape of airfrom the Ybottom of the high pressure chamber 2'9 toV the low` pressure c'ham'-v ber 30. Y

A series of agitators or plows 3l and a series of shorter agitators or plows 32 are xed to andro# tatable by the disk 33 which lies ony the top of the lbase 26 within the shel1`24 and the respective series of agitators project upwardly into the chambers 29 and 30 vto mix the fuel collected therein and cause it to flow-toward'the center of 4the receiver adjacent to the bottom mouth of thetube 2a.

A bevel gear 34, beneath `the top of the base 26, hasa hollow hub 35 projecting through an aper^ ture'in such base vand fixed to the disk 33 to ef fect the rotation of the latter.` A top-flanged' bushingl 3B is rotatably journa'lled inthe hollow hub 35v and has fixed therein a vertical shaft `3'! on which is fixed a helical worm 38 extending from the level of` the top of` the bushing 36A through the tube 28 to theftop thereof; `the edgel of Ithe worm making'a loose slip t with the inner periphery of the .tube 28. An eccentric spreader horn 38 is fixed to the shaft 31 above the top of the worm 38 and projects radially partly over the grate21. f'

The lower end of the lbushing 36 projects'downward through the bevel-gear 34 and has` fixed'v thereon a bevel gear'48 which meshes with'ja" bevel gear 4| vfixed to a shaft 42l journalled in bearings'in ythe base 2B. The shaft 42 alsolias` xed'thereto a'bevel-gear 43 which meshesy with the bevel gear 34. The bevel gears 43 and 4Irlie' on 'opposite sides of the concentric axes of the disk 33 and `shaft31 so that the" rotation ofthe shaft 42 effects theopposite rotations of the gears 1 foo 34 and 4I and therethrough of the agitator plowsr 3l and l32 and theworm 38 and spreader 39. y The shaft 42 maybe driven thru a sprocket 43a fixed thereon and connected by a chain `44j',` withv a sprocket 45 on the' shaft of the speedfk'A on the grate. spreading of 'fuel eventually provides a fuel bed Vlbed formed above the chamber 30 `and tHe/voli Ifand pressure zones of the grate may' be'v'ariedfin worm 38, the spreader 39, and the agitators 3l and 32 at pre-determined relative rates. The rotation of the Vanes 20 draws fuel and air from the hopper 2 through the tube 5 and extension I into the casing 8, from which they are expelled under pressure through the ducts 2 I, 22 and 23 into the receiver chamber 29.

When fuel blown into the chamber 29 has collected to a depth sufficient to seal the |bottom edges of the tube 28 and shell 25, the rotation of the worm v38 vbegins to elevate fuel through the tube 28 to the level of the inner edge of the grate 21 where it is engaged by the spreader 39 and pushed over ignited readily combustible material The continued accretion and of gradually decreasing depth over the entire grate area; with fresh coal of high volatile content nea the center, and partially consumed coal of lowvolatile content near the outer edge.

Aportion of the partially `consumedkcoal `and ash drops through the apertures in the grate into the chambers 29 and 30. lThere ,it ismixed with" the raw coal therein and yfed toward the worm 38 I bythe action of the plows 3l and 32 whichrotate V5counter to the direction of rotation of the worin" f'of the worm 4, and if desired the degree of suc-v tion and pressure produced by the blower may be varied by the adjustment of the opening of a vent 8a in the casing 8 adjacent -to the axis of the blowerrotor. Ordinarily, howeverysuch ad- 'justment need be made only with changes in the type, size or grade of fuel used. The fuel in the bin, in the feed tubes, in the collecting receiverA on the grate, control the admission and emission of air to and from the otherwise substantially ensclosed system and permit desired air pressure to be built up and maintained differentially at dif,-l ferent combustion zones of .the grate. By prop'- erly proportioning, relative to one another, 'the admission and emission of a particular fuel and Lair to the system, the proper ratio thereof'to one l another 'is secured and maintained.

As the air seals formed by the'fuel in the chambers 29` k and 38 and in the worm passages I and the limitedsize and number of the apertures 25a permit the maintenance of differential air pressures between the .chambers 29 and 30', air at higher pressure is available 'to penetrate the',` thicker fuelbed formed above .the harribe"1 28",Y than" is,- required to penetrate theY thinnerfuel;`

unies of'airsupplied t'o the respective Zonesar approximately proportioned to' 'the vcmnlmistiori,lj` requirements of the'fuel in the respective Zones.

TheI number of differential pressure chambers accrdanee withthe width of the grate;

The fu`el fed upward by the worin'lj'a follows the path of' least resistance towardthe surface" Y of the fuel bed above'theworrr.'V` Thespread'er matiofn ofa steep cone.

My'improvementsretain all theA advantages of Lrpnei'unatic'iconveyance 'of coalifrorn a"reservoi'rI a furnace and of over-feed central supply of fuel to a grate while also providing proper proportions of primary air to the fuel and positive feeding of coal at predetermined rates into and out of the conveyor system irrespective of the moisture content of the fuel.

My apparatus permits the maintenance of any desired rate of combustion of the fuel, maintains a predetermined re bed thickness, maintains the proper amount of air in the proper zones thus making it possible to burn a given amount of fuel at a high rate of eciency, and precludes the possibility of reverse flow of gaseous products of combustion through the fuel supply mechanism- Having described my invention, I claim;

1. In apparatus of the character described, the combination with an apertured grate, of a fuel collector beneath said grate, said collector containing a plurality of chambers communicating with apertures of said grate and adapted to be air-sealed from one another by fuel collected therein, means for maintaining differential airpressures in said chambers, and mechanism for elevating fuel from said collector to said grate and distributing it in the path of air emitted from said chambers.

2. In apparatus of the character described, the combination with an apertured grate, of a housing containing a, partition forming an inner chamber and an outer chamber below said grate and communicating with apertures of said grate, a conveyor for discharging fuel to said inner chamber, fuel agitators in at least one of said chambers, and mechanism for elevating the fuel from one of said chambers to said grate,

8. In apparatus of the character described, the combination with an apertured conoidal grate, of fuel collector containing chambers communicating. with said apertures and having concentric conoidal walls below said grate and a tube eX- tending downwardly from said grate, a worm rotatable in said tube, and agitators rotatable in said collector oppostely to the direction of rotation of said worm.

4. In apparatus of the character described, the combination with an apertured conoidal grate, of a means for collecting fuel below said grate and containing chambers communicating with apertures of said grate, said means having concentric conoidal Walls forming an inner chamber and an outer chamber connected through restricted ports in one of said walls, a fuel supply tube extending downwardly from said grate, and means for supplying fuel and air under pressure to said means first named.

5. In apparatus of the character described, the combination with a grate, of a fuel collector having a base beneath said grate, a rotor provided with agitators in said collector and having a gear beneath said base, means for discharging fuel to said collector, a worm in said collector for feeding fuel to said grate, means extending through said rotor and including a gear for rotating said worm, said Worm and rotor having` concentric axes, and a shaft having gears thereon on opposite sides of said axes for driving said worm and rotor in opposite directions.

6. In apparatus of the character described, the combination with an apertured conoidal grate, of a fuel collector below said grate and containing chambers communicating with apertures of said grate; said collector comprising a base, an outer wall, an inner wall shorter than said outer wall, and a fuel supply tube shorter than said inner wall, said inner wall containing restricted ports, a rotor in said collector and having agitators on opposite sides of said inner Wall, a gear beneath said base and connected with said rotor, a worm in. said fuel supply tube, a gear beneath said base and connected with said worm, and a shaft disposed transversely of the axes of said rotor and worm and having thereon gears connected with the gears aforesaid.

PAUL B. GREGER. 

